Method for Producing Patterned Materials

ABSTRACT

A large area patterned film includes a first patterned area; a second patterned area; and a seam joining the first patterned area and the second patterned area, wherein the seam has a width less than about 20 micrometers. A method for tiling patterned areas includes depositing a predetermined thickness of a curable material; contacting a first portion of the curable material with a mold; curing the first portion of the curable material; removing the mold from the cured first portion of the curable material; contacting a second portion of the curable material with the mold, such that the mold contacts a portion of the cured first portion of the curable material; curing the second portion of the curable material; and removing the mold to yield a seam between the cured first portion of the curable material and the cured second portion of the curable material, wherein the seam has a dimension less than about 20 micrometers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 61/120,327, filed Dec. 5, 2008, which is incorporatedherein by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with United States Government support undercooperative agreement number 70NANB7H7026 awarded by the NationalInstitute of Standards and Technology (NIST). The United Statesgovernment may have certain rights in this invention.

INCORPORATION BY REFERENCE

Each reference identified herein is hereby incorporated by reference asif set forth in its entirety.

BACKGROUND

There is a need to take small patterned areas (e.g., patterned siliconwafers) and expand their footprint in order to manufacture large areaproducts. Maintaining fidelity and mechanical strength in the large areaproduct is crucial to the products success. Expanding the footprint istypically done by “tiling” methods, through which one makes multiplecopies of the original pattern and abuts or tiles them together to forma larger pattern. The resulting patterned template can have the formfactor of a large flat area or cylindrical roll. Tiling methodscurrently in the art include various forms of physical and chemicalattachment including brackets, adhesives (e.g., tape, polymeric binders,epoxies, etc.), welding, and others. Ideally a minimal seam is created,for functional and aesthetic purposes. In production, large seams cancause trapping of fluid in low spots, poor contact between patternedroll and product film, mechanical weakening of the tool, loss offidelity of patterned areas, yield loss, visible “defects” in optical orviewing performance, and other drawbacks. These drawbacks can translateinto defects in the final product that can affect performance,particularly for films used in light management or display applications.

SUMMARY OF EMBODIMENTS OF THE INVENTION

There is a need in the art for fabricating high fidelity seams andmethods for producing such high fidelity seams between patterned areas.According to some embodiments of the present invention, a method fortiling patterned areas includes depositing a predetermined thickness ofa curable material; contacting a first portion of the curable materialwith a mold; curing the first portion of the curable material; removingthe mold from the cured first portion of the curable material;contacting a second portion of the curable material with the mold, suchthat the mold also contacts a portion of the cured first portion of thecurable material; curing the second portion of the curable material; andremoving the mold. In some embodiments, the method yields a seam betweenthe first cured portion of the curable material and the second curedportion of the curable material. In some embodiments, the seam has adimension less than about 20 micrometers. In some embodiments, thedimension of the seam is less than about 5 micrometers. In someembodiments, the dimension of the seam is less than about 500nanometers. In some embodiments, the dimension of the seam includes awidth or a height.

In some embodiments, prior to contacting the first portion of thecurable material with a mold, the curable material is cured to athickness less than the predetermined thickness such that a surface ofthe curable material remains substantially uncured. In some embodiments,the uncured material is substantially liquid. In some embodiments, athickness of the substantially uncured surface is controlled bycontrolling an oxygen concentration to which the curable material isexposed. In some embodiments, contacting the mold with the curablematerial substantially protects the curable material from oxygen. Insome embodiments, the mold is substantially transparent, for example, toUV light.

In some embodiments, curing the first portion of the curable materialincludes treating substantially all of the curable material withradiation while the first portion of the curable material issubstantially protected from exposure to oxygen by the mold. In someembodiments, curing the first portion of the curable material causes thefirst portion of the curable material to retain a pattern of the moldwhen the mold is removed from the first portion of the material. In someembodiments, curing the first portion of the curable material forms afirst patterned region in the curable material and curing the secondportion of the curable material forms a second patterned region in thecurable material. In some embodiments, a seam between the firstpatterned region and the second patterned region has a width less thanabout 5 micrometers. In some embodiments, a seam between the firstpatterned region and the second patterned region has a height less thanabout 1 micrometer.

According to some embodiments of the present invention, a method forfabricating a substantially seamless pattern includes providing a firstportion of curable material between a mold and a substrate proximate anip point; passing the first portion of curable material, the mold, andthe substrate through the nip point; curing the first portion of curablematerial; removing the mold from the first cured portion; providing asecond portion of curable material over at least a portion of the firstcured portion between the mold and the substrate; passing the secondportion of curable material, the mold, and the substrate through the nippoint; curing the second portion of curable material to form a secondcured portion; and removing the mold. In some embodiments, a seambetween the first cured portion and the second cured portion has adimension less than about 5 micrometers. In some embodiments, thedimension is less than about 1 micrometer. In some embodiments, thedimension is less than about 500 nanometers. In some embodiments, themold comprises a fluoropolymer. In some embodiments, the curablematerial is a radiation-curable polymeric material.

In some embodiments, passing the first portion of the curable material,the mold, and the substrate through a nip point results in depletion ofthe first portion of curable material prior to the mold and substrateexiting the nip point such that the curable material tapers to depletionbetween the mold and substrate. In some embodiments, providing thesecond portion of curable material includes adding the second portion ofcurable material to at least a portion of the depleted portion of thefirst cured portion such that the second portion substantially fills thetapered depletion to a pre-depletion thickness of curable material. Insome embodiments, curing the first portion of the curable materialcauses the first portion of curable material to retain a patternimparted from the mold after the mold is removed from the first portionof curable material. In some embodiments, curing the first portion ofthe curable material forms a first patterned region in the first curedportion and curing the second portion of curable material forms a secondpatterned region in the second cured portion. In some embodiments, aseam between the first patterned region and the second patterned regionhas a dimension less than about 250 nanometers.

According to some embodiments of the present invention, a method fortiling patterned areas includes distributing a first volume of curablematerial between a mold and a substrate, wherein when distributed thefirst volume undercoats the mold; curing the first volume to form afirst cured area; separating the mold from the substrate, wherein thefirst cured area remains coupled with and/or adjacent to the substrate;distributing a second volume of curable material adjacent the firstcured area between the mold and the substrate, wherein when distributedthe second volume undercoats the mold and overlaps the first cured area;curing the second volume to form a second cured area; and separating themold from the substrate, wherein the first and second cured areas remaincoupled with and/or adjacent to the substrate. In some embodiments, theoverlapped first and second cured areas results in a seam having adimension of less than about 20 micrometers. In some embodiments, thedimension is less than about 1 micrometer. In some embodiments, thedimension is a width of the seam. In some embodiments, the dimension isa height of the seam.

A large area patterned film, according to some embodiments of thepresent invention, includes a first patterned area; a second patternedarea; and a seam joining the first patterned area and the secondpatterned area, wherein the seam has a width less than about 20micrometers. In some embodiments, the seam has a height greater thanabout 50 nanometers and less than about 5 micrometer. In someembodiments, the width and/or height of the seam is less than about 5micrometers. In some embodiments, the width and/or height of the seam isless than about 1 micrometer. In some embodiments, the height of theseam is greater than about 50 nanometers and less than about 1micrometer. In some embodiments, the height of the seam is greater thanabout 50 nanometers and less than about 500 nanometers. In someembodiments, the width of the seam is less than about 5 micrometers andthe height of the seam is greater than about 50 nanometers and less thanabout 500 nanometers.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is made to the accompanying drawings which show illustrativeembodiments of the present invention and which should be read inconnection with the description of the invention.

FIGS. 1A-1E show a method according to an embodiment of the presentinvention;

FIGS. 2A-2F show a method according to another embodiment of the presentinvention;

FIGS. 3A-3F show a method according to another embodiment of the presentinvention;

FIGS. 4A-4F show a method according to another embodiment of the presentinvention;

FIGS. 5A-5C show a SEM and AFM images of a seam produced by a methodaccording to an embodiment of the present invention; and

FIG. 6 shows a SEM image of a seam produced by a method according toanother embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

According to some embodiments, the present invention includes methodsand systems for producing patterned materials. A method of the presentinvention includes contacting a curable material, for example, an ultraviolet (UV) curable material, with one or more molds or applying thecurable material to a substrate. In some embodiments, a method of thepresent invention includes engaging a first portion of a curablematerial with a first mold, curing the first portion of the curablematerial or all of the curable material in the presence of oxygen,engaging a second portion of the curable material with a second mold,and curing the second portion of the curable material while in contactwith the mold. In some embodiments of the present invention, the secondportion of the curable material includes, is adjacent to, or overlaps aportion of the first portion of the curable material, thereby forming alarge area substantially seamless article, drum, intermediate, or thelike. In some embodiments of the present invention, the second moldcontacts a portion of the first portion of the curable material. In someembodiments of the present invention, the first mold covers an areagreater than an area defined by the first portion of the curablematerial.

According to some embodiments, the present invention includes theproducts produced by any of the methods described herein. In someembodiments, the methods of the present invention create large areasubstantially seamless tiled articles or intermediate tools such as butnot limited to large area intermediate master templates or drums forroll-to-roll processing. Following the methods of the present inventionyields large area near-seamless tiled patterned areas of cured materialthat can be used as an article itself or which can be replicated withthe mold materials disclosed herein (and in the patent applicationincorporated herein by reference) which large area mold can then in turnbe used to produce large area near-seamless patterned area devices,displays, drums, tools, or the like.

Curable Material:

The curable material of the present invention may include any suitablecurable material known in the art. In some embodiments, the curablematerial of the present invention comprises, without limitation, one ormore polymers or monomers. In some embodiments, the curable material isdeformable prior to curing. In some embodiments, the curable material isin a substantially liquid state (e.g., flowable condition) prior tocuring. According to some embodiments, curing the curable material ofthe present invention includes hardening, for example, by chemicalreaction (e.g., polymerization), phase change, a melting/coolingtransition, evaporation, moisture cure, combinations thereof, and thelike. The curable material can also be a solution of one or morepolymers and/or monomers and one or more solvents and the curablematerial can cure (e.g., hardens) when the one or more solventsevaporate.

In some embodiments, the curable material cures when treated withradiation (e.g., UV-radiation). In some embodiments, the curablematerial comprises a UV-curable material (e.g., resin) that does notcure when exposed to oxygen (e.g., oxygen from the air). Most UV-curableresins are based on multifunctional monomers and oligomers whichgenerate highly cross-linked polymers by a photoinitiated radicalpolymerization. Free radicals formed by the photolysis of the initiatorare rapidly scavenged by oxygen molecules, thereby hinderingpolymerization. See, for example, Pieke and Heering, “Depth tracing theinfluence of oxygen on UV curing,” Proc. SPIE 6616, (2007), which isincorporated herein by reference in its entirety. In some embodiments, asurface layer of the curable material is exposed to oxygen (e.g., oxygenfrom the air) and remains substantially in an uncured state (e.g.,liquid state) when treated with radiation (e.g., UV-radiation), whereasa base layer of the curable material located between the surface layerof the curable material and a substrate is cured.

Examples of suitable curable materials useful in the present inventioninclude, without limitation, acrylates, methacrylates, vinyl monomers,butadienes, styrenes, propene, acrylonitrile, methacrylnitrile,acrylamide, methacrylamide allyl acetates, acetals, fumarates, maleates,ethylenes, propylenes, tetrafluoroethylene, ethers, isobutylene,fumaronitrile, acrylic acids, amides, imides, carbohydrates, esters,urethanes, siloxanes, formaldehyde, phenol, urea, melamine, isoprene,isocyanates, epoxies, bisphenol A, alcohols, silanes, dihalides, dienes,alkyl olefins, ketones, aldehydes, vinylidene chloride, anhydrides,saccharide, acetylenes, naphthalenes, pyridines, lactams, lactones,acetals, thiiranes, episulfide, peptides, cellulose, carbonates,polymers thereof, derivatives thereof, and combinations thereof.

Molds:

Molds useful in the present invention may have any suitableconfiguration known in the art for imparting one or more patterns ortextures to the curable material. In some embodiments, the molds usefulin the present invention are configured to impart a micro- and/ornanometer scale pattern to the curable material. In some embodiments, amold useful in the present invention includes a patterned sideconfigured to engage with (e.g., contact) the curable material and anunpatterned side opposite the patterned side. In some embodiments, amold useful in the present invention includes one or more cavitiesconfigured to accept (e.g., be filled by) the curable material. In someembodiments, a mold useful in the present invention includes a pluralityof cavities arranged in a predetermined pattern. In some embodiments,each cavity has a substantially predetermined size and/or shape. In someembodiments, the mold includes cavities having different sizes and/orshapes. In some embodiments, the mold includes micro and/or nano-sizedcavities. In some embodiments, the largest dimension of a cavity is fromabout 10 nm to about 500 micrometers.

In some embodiments of the present invention, the molds are constructedfrom one or more materials that are preferably flexible, non-toxic,substantially UV-transparent, tough, have a low surface energy, and aresubstantially resistant to swelling. In other embodiments, the molds aresubstantially rigid. The mold materials of the present invention,according to some embodiments, include photocurable and/or thermalcurable components, for example, materials that can be cured from aliquid to a solid upon application of a treatment such as actinicradiation or thermal energy. The properties of these materials can betuned over a wide range through the judicious choice of additives,fillers, reactive co-monomers, and functionalization agents. It will beappreciated that the materials described herein can be combined innumerous ways to form different mold materials for use in the presentinvention.

In preferred embodiments, a mold useful in the present invention isconstructed of a polymeric material. In some embodiments, the moldincludes a low surface energy polymer. In some embodiments, the moldincludes a fluoropolymer. In some embodiments, the mold includes apolymer chosen from the FLUOROCUR® resin series. In some embodiments,the mold is made by casting a thin film of curable polymer materialbetween a master template (e.g., a patterned silicon wafer) and apolymer sheet (e.g., PET), curing the polymer material, and removing thecured polymer material from the master template. In alternativeembodiments, the mold can be made in a thermoplastic material by hotembossing against a master template.

Preferred materials that can be useful with and/or as the mold materialsin the present invention include, in some embodiments, low surfaceenergy polymeric materials. Low surface energy molding materials providesuperior wetting properties and facile release from the curablematerials described in the present invention, yielding patternedsubstrates with high fidelity and minimal defects due to stiction. Insome embodiments, the mold can have a surface energy below about 25mN/m. In further embodiments, the mold can have a surface energy belowabout 20 mN/m. In still further embodiments, the mold can have a surfaceenergy below about 18 mN/m. In yet another embodiment of the presentinvention, the mold can have a surface energy below about 15 mN/m. Inyet another embodiment, the mold can have a surface energy below about12 mN/m.

In some embodiments, the mold can be a low surface energyelastomer-based material, for example, silicone, perfluoropolyether, ormaterial with similar characteristics. In some embodiments, the mold canbe or include a substantially solvent-resistant elastomer-basedmaterial, such as but not limited to a fluoropolymer, a fluorinatedelastomer-based material, a fluoropolyether, perfluoropolyether (PFPE),PFPE-based materials, combinations thereof, or the like. As used herein,the term “substantially solvent-resistant” refers to a material, forexample, an elastomeric material, that neither swells nor dissolvesbeyond a nominal amount in common hydrocarbon-based organic solvents oracidic or basic aqueous solutions. In some embodiments, the mold is madeof a substantially UV-transparent material.

In some embodiments, the molds used in the present invention include amaterial selected from the group including a fluoropolymer, aperfluoropolyether, a fluoroolefin, an acrylate, a silicone such as forexample polydimethylsiloxane (PDMS) or fluorinated PDMS, a polyether, astyrenic, a fluorinated thermoplastic elastomer (TPE), a triazinefluoropolymer, a perfluorocyclobutyl, a fluorinated epoxy, a fluorinatedmonomer or fluorinated oligomer that can be polymerized or crosslinked,a combination thereof, or the like.

In some embodiments the mold material is chosen to be compatible withthe curable material. Parameters that can affect compatibility caninclude chemical compatibility (i.e. substantially no reactivity orpermeability between mold and curable material), modulus, viscosity,surface energy, adhesion or the like. In some embodiments, a mold withhigher surface energy can be used to pattern a curable material with lowsurface energy.

In some embodiments, the molds used in the present invention includeflexible, patterned materials, such as metals, oxides, semiconductors,ceramics, and composites.

Further embodiments of molds of the present invention are disclosed inthe following references, which are hereby incorporated in theirentirety: WO 2005/084191 filed Feb. 14, 2005; U.S. 2007-0275193 filedAug. 11, 2006; and US 2008-0131692 filed Dec. 4, 2006.

Substrate:

In some embodiments of the present invention, the curable material isapplied to a substrate. The substrate can comprise any suitable materialknown in the art. In some embodiments, the substrate comprises one ormore of the materials described herein for molds useful in the presentinvention. In some embodiments, the substrate includes one or morepolymers (e.g, polycarbonate, acrylic, or PET). In some embodiments, thesubstrate includes one or more metals or semiconductors (e.g., steel,silicon, or aluminum). In some embodiments, the substrate is glass. Insome embodiments, the substrate may include at least one of a wafer,glass, plastic, polycarbonate, PEN, or PET. In some embodiments, thesubstrate is substantially uv-transparent; for example, a uv-transparentsubstrate could be used with an opaque mold using the methods describedherein.

In some embodiments, the substrate is substantially flexible. In otherembodiments, the substrate is substantially rigid. In some embodiments,the substrate is sacrificial. In some embodiment the substrate of thepresent invention includes substrates that have a selected affinity orlack of affinity for the curable materials of the present invention. Insome embodiments the substrate has a substantially planar surface towhich the curable material is applied. In some embodiments, thesubstrate has a substantially curved surface to which the curablematerial is applied. In some embodiments, the substrate is in the formof a sheet, plate, cylinder, film, disc, roller, wafer, or the like. Insome embodiments, the substrate, configured as a cylinder, roller, ordrum, once tiled as disclosed herein can be used as a device or tool forpatterning articles, films, mold making, or the like in a roll to rollor batch mode process. In yet other applications, the substrate is asheet and when tiled with patterned areas as described herein can be afilm or component of a display application, light managementapplications, photovoltaic devices, or the like. Also, the large areasubstantially seamless tiled patterned film can be used as anintermediate master from which a large area mold can be fabricated forprocessing large area substantially seamless patterned films, displayscreens, light management application components, photovoltaic devicecomponents, or the like.

In some embodiments, the substrate is coated with a layer containing oneor more adhesion promoters. The adhesion promoter can be a monomeric,oligomeric, or polymeric adhesion promoter or a solution including oneor more of these adhesion promoters. In some embodiments, the one ormore adhesion promoters are applied to the substrate in order to enhancethe affinity (e.g., bond strength) between the curable material and thesubstrate. Adhesion promoters useful in some embodiments of the presentinvention include any commercially available primers or adhesionpromoters known in the art that are compatible with the substrate andthe curable material. Preferably, the adhesion promoter comprises apolymeric adhesion promoter or a solution including one or morepolymeric adhesion promoters according to some embodiments of thepresent invention.

In some embodiments, wherein the substrate is a polymer substrate, theadhesion promoter is preferably a tie-layer polymer. In someembodiments, the tie-layer polymer is a linear polymer having a primarymonomeric component that is the same as or an analogue to the primarymonomeric component of the polymer substrate to be treated (e.g., suchthat the two respective polymers share solubilities in common solvents).In some embodiments, the tie-layer polymer further includes one or moremonomer units which each provide a reactive vinyl group (e.g., acrylic)as a side-chain on the tie-layer polymer backbone. In some embodiments,the vinyl moieties are randomly present along the tie-layer polymerchain. In some embodiments, application of the tie-layer polymer to thesubstrate results in reactive vinyl groups being presented on a surfaceof the substrate, the reactive vinyl groups being capable of formingcovalent linkages with the curable material (e.g., upon curing of thecurable material).

In some embodiments, the tie-layer polymer is applied to the polymersubstrate in a solution containing one or more solvents. In someembodiments, the one or more solvents are capable of dissolving thesubstrate polymer as well as the tie-layer polymer. In some embodiments,the tie-layer polymer solution is coated on the substrate in such a waythat the one or more solvents swell and/or partially dissolve a surfaceof the polymer substrate. This allows, in some embodiments, anintermixing of the substrate polymer and the tie-layer polymer,resulting in a pseudo-interpenetrating network between the substrate andthe tie-layer following evaporation and/or diffusion of the solvent(s)away from the substrate-tie-layer interface.

In some embodiments, the curable material is also the substrate. In someembodiments, the introduction of a suitable solvent to the substratesubstantially liquifies or dissolves a surface layer of the substrate.In some embodiments, the surface layer of the substrate is contactedwith a mold of the present invention and cured (e.g. hardened) bysolvent evaporation.

Oxygen Quenching Method:

A method according to some embodiments of the present invention includesapplying a layer of curable material to a substrate, contacting a firstportion of the curable material with a first mold, curing the firstportion of the curable material, removing the first mold from the firstportion of the curable material, contacting a second portion of thecurable material with a second mold, curing the second portion of thecurable material, and removing the second mold from the second portionof the curable material.

In some embodiments, the curable material may comprise one or more ofthe curable materials described above and herein. Preferably, thecurable material comprises a UV-curable material (e.g., a UV-curablepolymer). In some embodiments, the layer of curable material is appliedto the substrate at a predetermined thickness. In some embodiments, thepredetermined thickness is from about 50 nm to about 100 micrometers. Insome embodiments, the layer of curable material is applied, for example,with a mayer rod, a slot coater, a doctor blade, a nip point, freemeniscus or dip coating, or other suitable means known in the art. Insome embodiments, the curable material is substantially in a flowablecondition (e.g., uncured, liquid state) when applied to the substrate.In some embodiments, the layer of curable material includes a surfacethat is exposed to oxygen (e.g., exposed to air or otheroxygen-containing environment). In some embodiments, the surface that isexposed to oxygen is substantially parallel to a surface of thesubstrate on which the layer of curable material is applied.

The substrate may comprise one or more of the substrate materialsdescribed above and herein. In some embodiments, the substrate is apolymer (e.g, polycarbonate, acrylic, or PET). In some embodiments, thesubstrate is a metal or semiconductor (e.g., steel, silicon, oraluminum). In some embodiments, the substrate is glass. In someembodiments, the substrate may include at least one of a wafer, glass,plastic, polycarbonate, PEN, or PET. In some embodiments, the substrateis substantially rigid. In some embodiments the substrate issubstantially flexible. In some embodiments, the curable materialadheres strongly to the substrate. In some embodiments, the curablematerial substantially wets one of more of the mold surface and thesubstrate surface. In some embodiments, an adhesion promoter (e.g., atie-layer polymer) is applied to the substrate surface prior toapplication of the curable material to the substrate. In someembodiments, the substrate and the curable material have at least onecomponent in common. In some embodiments the substrate has asubstantially planar surface to which the curable material is applied.In some embodiments, the substrate has a substantially curved surface towhich the curable material is applied. In some embodiments, thesubstrate is in the form of a sheet, plate, film, disc, or wafer. Insome embodiments, the substrate is in the form of a cylinder or roller.

In some embodiments, the curable material is initially cured after beingapplied to the substrate. In some embodiments, the curable material isinitially cured to a thickness less than the predetermined thickness ofthe curable material. In some embodiments, the initial curing includestreating the curable material such that a base layer of the curablematerial cures (e.g., hardens) while a surface layer of the curablematerial remains substantially uncured (e.g., substantially in a liquidstate), the base layer being between the surface layer of the curablematerial and the substrate. In some embodiments, the thickness of thecured base layer and the uncured surface layer can be controlled byvarying parameters, for example, initiator concentration, the additionof free radical scavengers, oxygen concentration, and UV exposureintensity and duration. In some embodiments, the thickness of the baselayer is substantially larger than the thickness of the surface layer.In some embodiments, the thickness of the curable material layer iscontrolled such that substantially the entire layer remains uncured uponexposure to UV light in the presence of oxygen.

In some embodiments, a first mold is applied to a first portion of thecurable material. In some embodiments, the first mold is applied suchthat the first portion of the curable material is positioned between thefirst mold and the substrate. In some embodiments, the first portion ofthe curable material is the portion of the curable material covered bythe first mold. In some embodiments, the first mold includes a patternwhereby the first portion of the curable material conforms to (e.g.,fills) the pattern of the first mold. In some embodiments, the firstmold is constructed of one or more polymeric materials, as describedherein. In some embodiments, the first mold is UV-transparent. In someembodiments, the first mold includes a fluoropolymer, silicone,polyether, or the like. In some embodiments, the first mold includes apolymer chosen from the FLUOROCUR® resin series. In some embodiments,the first mold is made by casting a thin film of curable polymermaterial between a master template and a polymer sheet, curing thepolymer material, and removing the cured polymer material from themaster template.

In some embodiments, the first mold is applied to the first portion ofthe curable material manually (e.g., by hand, using a roller). In someembodiments, the first mold is applied to the first portion of thecurable material by an automated system (e.g., by a laminator). In someembodiments, the first mold is applied to the first portion of thecurable material by passing the first mold and the first portion of thecurable material through a nip point.

In some embodiments, the first portion of the curable material is thencured. In some embodiments, the first portion of the curable material iscured while engaged with (e.g., contacting) the first mold such that apattern imparted by the first mold to the first portion of the curableis substantially retained in the cured material. In some embodiments,the first portion of the curable material is cured by treating the firstportion of the curable material with radiation. In some embodiments, thefirst portion of the curable material is cured by treating the firstportion of the curable material with UV-radiation (e.g., UV light). Insome embodiments, curing the first portion of the curable materialincludes treating substantially the entire layer of curable materialwith radiation (e.g., UV-radiation). In some embodiments, the first moldsubstantially protects the first portion of the curable material fromexposure to oxygen, thereby allowing the first portion of the curablematerial to cure. In some embodiments, uncured areas of the curablematerial exposed to oxygen remain in a substantially uncured (e.g.,liquid) state when treated with radiation. For example, in someembodiments, uncured areas of the curable material that are not engagedwith the first mold may be exposed to oxygen and remain uncured. In someembodiments, the first mold is removed from the first portion of thecurable material after curing the first portion of the curable material.

In some embodiments, a second portion of the curable material iscontacted with a second mold. In some embodiments, the second portion ofthe curable material is the portion of the curable material other thanthe first portion of the curable material that is covered by the secondmold. In some embodiments, the second portion of the curable materialincludes a cured base layer and an uncured surface layer. In someembodiments, the second portion of the curable material is adjacent tothe first portion of the curable material. In some embodiments, thesecond portion of the curable material is spaced a distance away fromthe first portion of the curable material.

In some embodiments, the second mold and the first mold havesubstantially the same physical and/or chemical characteristics. In someembodiments, the second mold and the first mold are the same mold, i.e.the first mold is reused. In some embodiments, the second mold and thefirst mold are different. In some embodiments, the second mold has apattern different than a pattern on the first mold. In some embodiments,the second mold and the first mold are constructed from the samematerial. In some embodiments, the second mold is constructed of apolymeric material. In some embodiments, the second mold isUV-transparent. In some embodiments, the second mold includes afluoropolymer, silicone, polyether, or the like. In some embodiments,the second mold includes a polymer chosen from the FLUOROCUR® resinseries. In some embodiments, the second mold is made by casting a thinfilm of curable polymer material between a master template and a polymersheet curing the polymer material, and removing the cured polymermaterial from the master template. In some embodiments, the second moldis applied to the second portion of the curable material manually (e.g.,by hand, using a roller). In some embodiments, the second mold isapplied to the second portion of the curable material by an automatedsystem (e.g., by a laminator). In some embodiments, the second mold isapplied to the second portion of the curable material by passing thesecond mold and the second portion of the curable material through a nippoint. In some embodiments, the second mold is positioned so as to alsocontact (e.g., cover or overlay) a portion of the cured first portion ofthe curable material. In some embodiments, the second mold issubstantially flexible such that the second mold can bend at or near apoint of contact with the cured first portion of the curable material.

In some embodiments, the second portion of the curable material is curedwhile engaged with (e.g., contacting) the second mold such that apattern imparted by the second mold to the second portion of the curableis substantially retained in the cured material. In some embodiments,curing the second portion of the curable material includes treating thesecond portion of the curable material with radiation (e.g.,UV-radiation). In some embodiments, curing the second portion of thecurable material includes treating substantially the entire layer ofcurable material with radiation (e.g., UV-radiation). In someembodiments, the second mold substantially protects the second portionof the curable material from exposure to oxygen, thereby allowing thesecond portion of the curable material to harden when cured. In someembodiments, the second mold is removed from the second portion of thecurable material after curing the second portion of the curablematerial. In some embodiments, any remaining uncured material is removedfrom the substrate.

In some embodiments, the height of the seam is substantially equivalentto the height of the uncured surface layer of curable material. In someembodiments, the height of the seam is less than the height of theuncured surface layer of curable material.

In some embodiments, a seam is produced between the first and secondportions of the curable material. In some embodiments, the seam has awidth from about 50 nm to about 20 micrometers. In some embodiments, theseam has a width from about 50 nm to about 10 micrometers. In someembodiments, the seam has a width from about 20 nm to about 5micrometers. In some embodiments, the seam has a width from about 10 nmto about 5 micrometers. In some embodiments, the seam has a width fromabout 20 nm to about 1 micrometer. In some embodiments, the seam has awidth from about 10 nm to about 500 nanometers. In some embodiments, theseam has a width of less than about 20 micrometers. In some embodiments,the seam has a width of less than about 5 micrometers. In someembodiments, the seam has a width of less than about 1 micrometer. Insome embodiments, the seam has a width of less than about 500nanometers. In some embodiments, the seam has height from about 10 nm toabout 10 micrometers. In some embodiments, the seam has height fromabout 10 nm to about 5 micrometers. In some embodiments, the seam hasheight from about 10 nm to about 1 micrometer. In some embodiments, theseam has height from about 10 nm to about 500 nanometers. In someembodiments, the seam has height from about 10 nm to about 250nanometers. In some embodiments, the seam has height from about 10 nm toabout 100 nanometers. In some embodiments, the seam has a height of lessthan about 10 micrometers. In some embodiments, the seam has a height ofless than about 5 micrometers. In some embodiments, the seam has aheight of less than about 1 micrometer. In some embodiments, the seamhas a height of less than about 500 nanometers. In some embodiments, theseam has a height of less than about 250 nm. In some embodiments, theseam has a height of less than about 100 nm.

The term “seam” means a disturbed or affected area between or adjacentone or more patterned areas, where the disturbed or affected area can bein the horizontal or width direction of a plane, in the vertical orheight direction extending from a plane, or the combination of width andheight disturbance. It should be understood that the adjacent oradjoining patterned areas adjoined by the seam can be aligned in anordered manner, such as an ordered array, but the patterns of theadjacent patterned areas do not necessarily need to be aligned in anyparticular manner. Furthermore, the patterns of the adjacent patternedareas do not need to be the same or similar patterned structures as someapplications may require or benefit from tiling patterns of altering ordifferent structures. The disturbance or affected area defining the seamcan be disturbed structures that are not replicated with high precisionor fidelity, such as partial structure replication, or the disturbanceor affected area can be lacking all or substantially all structures ofthe adjacent patterned areas.

In some embodiments, one or more masks may be applied to (e.g., cover)selected portions of the curable material to prevent the selectedportions of the curable material from curing. In some embodiments, onlythe unmasked portions of the curable material are capable of beingcured. The one or more masks are preferably configured to substantiallyprevent exposure of the curable material to radiation that wouldotherwise cause the curable material to cure. For example, asubstantially UV-opaque mask applied to a UV-curable material willsubstantially prevent the curable material from curing during treatmentwith UV-radiation by protecting the covered portion from theUV-radiation. In some embodiments, the use of masks permits the curingsteps to proceed in an atmosphere substantially free of oxygen. In someembodiments, one or more masks are applied to selected areas of thecurable material that are not engaged with the first and/or second moldsso as to substantially prevent curing of these areas of the curablematerial during curing of the first and second portions of the curablematerial. In some embodiments, one or more masks (e.g., UV-opaque masks)are applied to the unpatterned sided of the first and/or second mold,either directly or as a separate layer, such that only the areas of thecurable material engaged with the unmasked portion of the mold will becured when treated with radiation.

In some embodiments, the UV light may be focused onto selected portionsof the curable material to prevent the unselected portions of thecurable material from curing. In some embodiments, only the portions ofthe curable material in contact with the focused UV light are capable ofbeing cured. In some embodiments, the use of focused UV light permitsthe curing steps to proceed in an atmosphere substantially free ofoxygen. In some embodiments, the focused UV light is applied only toselected areas of the curable material that are engaged with the firstand/or second molds so as to cure only these areas of the curablematerial during curing of the first and second portions of the curablematerial.

FIGS. 1A-1E shows one embodiment of a method according to the presentinvention that can be used, for example, for making large areasubstantially seamless tiled patterned devices useful as end products indisplays, photovoltaic devices, light management devices, or the like oruseful as intermediate master devices for fabricating large areasubstantially seamless patterned molds. A layer of curable material 100,for example, a UV-curable liquid resin, is applied (e.g., cast) ontosubstrate 200 at a predetermined thickness T such that a surface layer102 of the layer of curable material 100 is exposed to oxygen. Surfacelayer 102 has a thickness that is less than the predetermined thicknessT of the layer of curable material 100. Optionally, the curable material100 is initially cured after application onto substrate 200 by, forexample, treating the layer of curable material 100 with radiation(e.g., UV-radiation). In one embodiment, because surface layer 102 isexposed to oxygen, the surface layer 102 remains substantially uncuredwhile base layer 104 is cured.

Following the initial curing, a first portion 106 of the curablematerial 100 is engaged with (e.g., contacted by) a first mold 300.First mold 300 may be applied to the first portion 106 of the curablematerial 100 manually, for example, by using a roller, or by anautomated process, for example, by using a laminator. First mold 300 mayhave any suitable configuration known in the art. Preferably, first mold300 is made from a flexible, UV-transparent material. In someembodiments, first mold 300 is made from one or more of the moldmaterials as described above. In some embodiments, first mold 300includes a plurality of cavities 302 which may be arranged in one ormore predetermined patterns. The uncured material of first portion 106substantially conforms to first mold 300 when engaged with first mold300, for example, by flowing into cavities 302 of first mold 300.Preferably, first mold 300 substantially protects first portion 106 ofcurable material 100 from exposure to oxygen.

First portion 106 of curable material 100 is then cured. Curing firstportion 106, in some embodiments, includes treating first portion 106with UV-radiation while engaged with a UV-transparent first mold 300.The UV-radiation passes through first mold 300 to cure (e.g.,polymerize) the uncured material of first portion 106 while first mold300 substantially protects first portion 106 from exposure to oxygen.The uncured portions of curable material 100 that are not engaged withfirst mold 300 remain exposed to oxygen and therefore remain uncuredduring the treatment with radiation.

Following the curing of first portion 106, first mold 300 is removedfrom cured first portion 106. A second portion 108 of curable material100 is then engaged with a second mold 304. Second portion 108 may besubstantially uncured or may include a layer of uncured material and alayer of cured material. In some embodiments, as shown in FIG. 1D,second portion 108 is adjacent to cured first portion 106. In someembodiments, second portion 108 is spaced a distance away from curedfirst portion 106.

In some embodiments, second mold 304 is positioned such that it contacts(e.g., overlays or covers) a portion of the cured first portion 106.Preferably, second mold 304 substantially protects second portion 108 ofcurable material 100 from exposure to oxygen. In some embodiments,second mold 304 and first mold 300 are the same mold. In someembodiments, second mold 304 and first mold 300 are different molds. Insome embodiments, second mold 304 includes a plurality of cavities 306that may be arranged in a predetermined pattern that is the same as ordifferent than a pattern of the first mold 300. In some embodiments,second mold 304 has the same physical and/or chemical characteristics asfirst mold 300. Preferably, second mold 304 is made from a substantiallyflexible, UV-transparent material.

Curing the second portion 108 of curable material 100, in someembodiments, includes treating the second portion 108 with radiation ina manner substantially similar to curing the first portion 106. Forexample, second portion 108 may be cured by treating second portion 108with UV-radiation while engaged with a UV-transparent second mold 304.The UV-radiation passes through UV-transparent second mold 304 to cure(e.g., polymerize) the uncured material of second portion 108 whilesecond mold 304 substantially protects second portion 108 from exposureto oxygen. The uncured portions of curable material 100 that are notengaged with second mold 304 remain exposed to oxygen and thereforeremain uncured during the treatment with radiation. Following the curingof second portion 108, second mold 304 is removed from cured secondportion 108. As shown in FIG. 1E, a seam 110 may be formed where thecured first portion 106 and the cured second portion 108 are joined. Insome embodiments, seam 110 has a maximum width of about 10 nm to about20 micrometers. More preferably, seam 110 has a maximum height of about10 nm to about 5 micrometers. In one embodiment, FIG. 1E shows a largearea substantially seamless patterned area intermediate master, mold, orarticle (depending on the application).

Starved Bead Method

In some embodiments, a method according to the present inventionincludes providing a first portion of a curable material between a firstmold and a substrate; contacting the first portion of the curablematerial with the first mold; curing the first portion of the curablematerial; removing the first mold from the first portion of the curablematerial; providing a second portion of the curable material over atleast a portion of the cured first portion of the curable materialbetween a second mold and the substrate; contacting the second portionof the curable material with the second mold; curing the second portionof the curable material; and removing the second mold from the secondportion of the curable material.

In some embodiments, providing a portion of curable material between amold and a substrate includes applying the curable material to a surfaceof the substrate, as described previously. In some embodiments,providing a portion of curable material between a mold and a substrateincludes applying the curable material to the mold. In some embodiments,a patterned surface of the mold is coated with the curable material. Insome embodiments, the curable material is introduced, at leastpartially, into one or more cavities of the mold. In some embodiments,the portion of curable material covers an area smaller than the areacovered by the mold.

In some embodiments, a method according to the present inventionincludes providing a first portion of a curable material proximate a nippoint between a first mold and a substrate; passing the first portion ofthe curable material, the first mold, and the substrate through the nippoint; curing the first portion of the curable material; removing thefirst mold from the first portion of the curable material; providing asecond portion of the curable material over at least a portion of thecured first portion of the curable material between a second mold andthe substrate; passing the second portion of the curable material, thesecond mold, and the substrate through the nip point; curing the secondportion of the curable material; and removing the second mold from thesecond portion of the curable material.

In some embodiments, the nip point is formed between a roller and asurface. In some embodiments, the nip point is formed between a firstroller and a second roller. In some embodiments, an edge of the firstmold and the substrate are nipped at the nip point prior to providingthe first portion of the curable material between the first mold and thesubstrate. In some embodiments, an edge of the second mold and thesubstrate are nipped at the nip point prior to providing the secondportion of the curable material between the second mold and thesubstrate. In some embodiments, passing the first portion of the curablematerial, the first mold, and the substrate through the nip point causesthe first portion of the curable material to spread (e.g., roll out)into a layer upon the substrate. In some embodiments, passing the secondportion of the curable material, the second mold, and the substratethrough the nip point causes the second portion of the curable materialto spread (e.g., roll out) into a layer upon the substrate. In someembodiments, the layer of curable material has a region of reducedthickness where the volume of curable material is exhausted prior toreaching at least one edge of the mold (e.g., a starve point or trailingedge). In some embodiments, the region of reduced thickness is at aperiphery of the layer.

In some embodiments, the second portion of the curable material isprovided over a portion of the first portion of the curable materialafter the first portion of the curable material is cured. In someembodiments, the second portion of the curable material is provided overthe region of reduced thickness (e.g., the starve point or trailingedge) of the cured first portion of the curable material.

In some embodiments, the first and second portions of the curablematerial each have a predetermined volume. In some embodiments, thepredetermined volume is selected such that the entire volume of thefirst and second portions of the curable material are covered by thefirst and second molds, respectively. In some embodiments, thepredetermined volume is selected such that first and second portions ofthe curable material each produce a layer of curable material on thesubstrate having an area less than the areas covered by the first moldand second molds, respectively. In some embodiments, the first andsecond molds are configured to extend beyond the volumes of the firstand second portions of the curable material, respectively. In someembodiments, at least part of the first and/or second molds whichextends beyond the volumes of the first and/or second portions of thecurable material contacts a surface of the substrate. In someembodiments, the volume of curable material is determined by thecharacteristics of one of more of the mold, the curable material, or theprocessing parameters. In some embodiments, the characteristics includethe volume of cavities in the mold, the desired thickness of patternedlayer, the surface energy of one or more of the mold, substrate, andcurable material, the viscosity of the curable material, the area of themold, the speed and pressure of the roller, or the like.

FIGS. 2A-2F shows one embodiment of a method according to the presentinvention. In this embodiment, a first portion 400 of a curable material(e.g., a UV-curable resin) is provided between a first mold 600 and asubstrate 500 proximate a nip point 700. First portion 400 may beapplied as one or more beads of curable material and may have apredetermined volume. First mold 600 is preferably constructed from asubstantially flexible, UV-transparent material and includes a pluralityof cavities 602 configured to accept the curable material of firstportion 400. Nip point 700 is formed between a first roller 702 and asecond roller 704, which may rotate in opposite directions, as indicatedby the arrows. Prior to providing the first portion 400 of the curablematerial, an edge 604 of first mold 600 and substrate 500 may be nippedat nip point 700.

As the first portion 400 of the curable material, the first mold 600,and the substrate 500 are passed through nip point 700, as shown in FIG.2B, first mold 600 and substrate 500 are pressed towards each othercausing the curable material of first portion 400 to substantially fillcavities 602 and causing first portion 400 to spread into a layer uponsubstrate 500. The layer may include a region 402 having a reducedthickness, located at a periphery of the layer, which is formed as thevolume of first portion 400 is exhausted. Portion 606 of mold 600 thatextends beyond first portion 400 of the curable material may come intocontact with substrate 500.

While first portion 400 of the curable material is engaged with firstmold 600, first portion 400 is cured, for example, by treatment withUV-radiation. After curing, the first mold 600 is removed from firstportion 400. First portion 400, now cured, substantially retains apattern imparted by first mold 600, as shown in FIG. 2C.

A second portion 404 of the curable material is then provided between asecond mold 608 and the substrate 500 proximate nip point 700.Preferably, second portion 404 at least partially overlays the curedfirst portion 400. In the embodiment shown in FIG. 2D, second portion404 is provided over region 402 of first portion 400. Second mold 608may include a plurality of cavities 610 and may have a configurationsubstantially the same as or different than first mold 600. In someembodiments, second mold 608 and first mold 600 are the same mold. Anedge 612 of second mold 608 may be nipped with substrate 500 prior toproviding the second portion 404 of the curable material. As shown inFIG. 2D, edge 612 of second mold 608 may be nipped with substrate 500 ator proximate to region 402 of the cured first portion 400.

The second portion 404, the second mold 608, and the substrate 500 arethen passed through nip point 700, pressing second mold 608 andsubstrate 500 towards each other and causing the curable material ofsecond portion 404 to substantially fill cavities 610, and causingsecond portion 404 to spread into a layer upon substrate 500. The layerformed from second portion 404 overlays region 402 of cured firstportion 400 and may also include a region 406 having a reducedthickness, which is formed as the volume of second portion 404 isexhausted.

While second portion 404 of the curable material is engaged with secondmold 608, second portion 404 is cured, for example, by treatment withUV-radiation. After curing, the second mold 608 is removed from secondportion 404. Second portion 404, now cured, substantially retains apattern imparted by second mold 608, as shown in FIG. 2C. A seam 408 maybe formed where the cured first portion 400 and the cured second portion404 are joined. Preferably, seam 408 has a maximum width of about 10 nmto about 20 micrometers. Preferably, seam 408 has a height of about 10nm to about 5 micrometers. Repeating this process can yield a large areasubstantially seamless tiled patterned intermediate tool from which alarge area substantially seamless mold or article can be fabricated.

FIGS. 3A-3F shows another embodiment of a method according to thepresent invention. According to this embodiment, a surface of substrate1200 is coated with a curable material 1100 (e.g., a UV-curable resin)that is substantially in a liquid state. One or more adhesion promoters(e.g., tie-layer polymer) may be optionally applied to the surface ofsubstrate 1200 prior to coating with the curable material 1100 in orderto enhance bonding between substrate 1200 and curable material 1100,increase durability, reduce defects, increase surface or materialuniformity, and the like. The curable material 1100 is then contacted bya first mold 1300 (e.g., a UV-transparent mold), which can be applied tothe curable material 1100 by any suitable means. For example, first mold1300 can be rolled onto curable material 1100 in the direction shown bythe arrow in FIG. 3C manually using a roller or applied using alaminator. While engaged with first mold 1300, the curable material 1100is treated with UV radiation in the presence of oxygen. As illustratedin FIG. 3D, only the portion of curable material 1100 that was coveredby first mold 1300 is cured by the UV radiation since only the portionof curable material 1100 covered by first mold 1300 was protected fromoxygen. Following the curing step, first mold 1300 is removed, revealinga first cured portion 1106 having an area substantially equal to thearea that was covered by first mold 1300. A second mold 1304, which maybe the same mold as first mold 1300, is then applied to a second area ofcurable material 1100. Preferably, second mold 1304 is positioned tooverlap (e.g., contact) at least a portion of cured portion 1106. Again,second mold 1304 may be applied by any suitable means, for example, bybeing rolled onto curable material 1100 in the direction indicated bythe arrow in FIG. 3E. After application of second mold 1304, the curablematerial 1100 is treated once more with UV radiation in the presence ofoxygen so as to only cure the uncured portion of curable material 1100that is covered by second mold 1304. Uncovered portions of curablematerial 1100, apart from first cured portion 1106, remain uncured dueto exposure to oxygen. Following the second curing step, second mold1304 is removed revealing second cured portion 1108, which is joined tofirst cured portion 1106 by a seam 1110. Repeating this process canyield a large area substantially seamless tiled patterned intermediatetool from which a large area substantially seamless mold or article canbe fabricated.

FIGS. 4A-4F show yet another embodiment of a method according to thepresent invention. In this embodiment, UV-transparent first mold 2300 isprovided having a patterned side and an unpatterned side. A UV-opaquemask 2800 is applied to the unpatterned side of a UV-transparent firstmold 2300. A curable material 2100 (e.g., a UV-curable material) is thenapplied to the patterned side of first mold 2300 and is brought incontact with a substrate 2200 such that the curable material 2100 issubstantially positioned between first mold 2300 and substrate 2200. Forexample, first mold 2300 coated with curable material 2100 may be rolledonto substrate 2200 in the direction shown by the arrow in FIG. 4C.Optionally, one or more additional UV-opaque masks 2804 can be appliedin any desired arrangement. For example, an additional UV-opaque mask2804 may be positioned to cover portions of substrate 2200 not coveredby first mold 2300 or be applied to cover additional portions of theunpatterned side of first mold 2300. UV-radiation treatment then followssuch that the portion of curable material 2100 not covered by UV-opaquemasks 2800 and 2804 is cured. Any portion of curable material 2100 thatwas covered by UV-opaque masks 2800 and 2804 remain uncured because thisportion would not have been exposed to the UV-radiation. Any uncuredmaterial remaining on substrate 2200 following the removal of first mold2300 and masks 2800 and 2804 may be optionally washed away (e.g., usingisopropyl alcohol or other suitable solvent), thus leaving only curedportion 2106 on substrate 2200. A second mold 2304, having anunpatterned side with UV-opaque mask 2802 and a patterned side coatedwith additional curable material 2102 may then be applied to substrate2200, for example, rolled onto substrate 2200 in the direction indicatedby the arrow in FIG. 8E. In one variation, second mold 2304 is the sameas first mold 2300. Preferably, second mold 2304 is positioned toslightly overlap an area of cured portion 2106. Additional UV-opaquemasks 2804 may optionally be applied again in any desired arrangement,followed by treatment with UV-radiation. Only portions of curablematerial 2102 not covered by UV-opaque masks 2802 and 2804 are cured,and any portions of curable material 2102 covered by UV-opaque masks2802 and 2804 remain uncured. Following removal of second mold 2304 andmasks 2802 and 2804, any uncured material remaining on substrate 2200may be optionally washed away (e.g., using isopropyl alcohol or othersuitable solvent), thus leaving only cured portions 2106 and 2108remaining on substrate 2200, which are joined by seam 2110. Repeatingthis process can yield a large area substantially seamless tiledpatterned intermediate tool from which a large area substantiallyseamless mold or article can be fabricated.

Example 1 Synthesis of Tie Layer Materials

Synthesis of Poly[(Methyl Methacrylate)-Co-(2-HydroxyethylMethacrylamide).

Methyl methacrylate (35.8 g), 2-hydroxyethyl methacrylamide (6.4 g), and2,2′-azobisisobutyronitrile (0.16 g) in N,N-Dimethylformamide (60 g)were heated 5 h at 80° C. The cooled solution was precipitated intoethyl ether (300 mL), redissolved in tetrahydrofuran (200 mL) andprecipitated again into ethyl ether (300 mL). Residual solvents wereremoved under reduced pressure to afford 41 g of product (97%).

Synthesis of Poly[(Methyl Methacrylate)-Co-(2-[Methacryloxy]EthylMethacrylamide)].

A solution of Poly[(methyl methacrylate)-co-(2-hydroxyethylmethacrylamide) (41 g), as prepared above, in toluene (100 mL) wastreated with 2,6-di-tert-buyl-4-methylphenol (1.1 g), methyacrylicanhydride (14.8 mL), and N-methylimidazole (0.4 g) and heated 15 h at90° C. The cooled solution was precipitated into ethyl ether (300 mL),redissolved in chloroform (100 mL) and precipitated into ethyl ether(300 mL) twice. Residual solvents were removed under reduced pressure toafford 34.7 g product.

Example 2

Thin FLUOROCUR® molds were produced by laminating a thin film ofFluorocur OAE-01 resin between a master template having a patternedarray of 200×200 nm cylindrical posts and a 6″ wide sheet of PET(MELINEX® D316, DuPont Teijin Films). The mold was placed in a UV floodcuring chamber and exposed to UV (approximate output of 125 mW/cm²) for4 minutes. The PET-Fluorocur laminate was then peeled from the masterand trimmed. The approximate patterned area of the mold is 5″×5″ square.The Fluorocur thin molds are then used to tile a larger area pattern onan acrylic substrate using the following steps.

The acrylic surface is first prepared with a tie layer. A solution ofpoly[(methyl methacrylate)-co-(2-(methacryloxy)ethyl methacrylamide] (15w/w % in chloroform) is applied via lamination (15 psi) between thepolymer substrate and a PET cover sheet and remains laminated untildiffusion of the chloroform into the bulk of the polymer substrate andaway from the interface has occurred (typically 15 h or longer). Thecover sheet is then removed to afford a surface with the topology of thecover sheet with grafted methacrylic reactive moieties for covalentadhesion to the UV-curable resin.

Coat the treated side of the acrylic substrate with a uniform thin layerof TEGO RC 711, a UV curable resin, formulated with 1%diphenyl(2,4,6-trimethylbenzoyl)phosphineoxide/2-hydroxy-2-methylpropiophenone blend as a photoinititiator usinga #7 Mayer rod from a 20% solids mixture in isopropyl alcohol. Uniformlyroll out a Fluorocur thin mold to the coated acrylic pattern side downusing a rubber roller, rolling in the direction parallel to the seam,for example, as shown in the embodiment depicted in FIG. 3C. The TEGO RC711 resin fills the cavities of the mold completely. Place the substrateinto the UV flood chamber and cure for 4 minutes. Peel the Fluorocurmold from the substrate. The area underneath the mold exposed to the UVhas cured into a pattern that reflects the pattern of the mold, whilethe area around the mold does not cure at the surface. A second mold isthen applied to the substrate in a similar matter, where a portion ofthe second mold overlaps the cured patterned area. The substrate isplaced into the UV chamber and cured for 4 minutes. The second mold isthen removed to reveal a second cured, patterned area adjoining thefirst by a seam. The dimensions of this seam are approximately 1micrometer wide with a step height of <200 nm. SEM and AFM images ofthis seam are given in FIGS. 5A-5C.

Example 3

Thin FLUOROCUR® molds were produced by laminating a thin film ofFluorocur resin (OAE-01) between a master template having a patternedarray of 200 nm diameter×600 nm height cylindrical posts and a 6″ widesheet of PET (MELINEX® D316, DuPont Teijin Films). The mold was placedin a UV flood curing chamber and exposed to UV (approximate output of125 mW/cm²) for 4 minutes. The PET-Fluorocur laminate was then peeledfrom the master and trimmed. The approximate patterned area of the moldis 5″×5″ square. The Fluorocur thin molds are then used to tile a largerarea pattern on PET using the following steps.

Place 5 Mil PET substrate (MELINEX® 453, DuPont Teijin Films), treatedside up on a steel plate laminator, and nip the edge of the mold on theacrylic substrate using a rubber roller (durometer 60) at a nip pressureof ˜15 psi. Apply a bead of uv curable liquid (Trimethylolpropaneethoxylate (14/3 EO/OH triacrylate, average Mn 428, Sigma-Aldrich, 1 w/w% diphenyl(2,4,6-trimethylbenzoyl)phosphineoxide/2-hydroxy-2-methylpropiophenone 50:50 blend) at the nip point.Uniformly roll the mold in contact with the substrate at a rate of 0.5-1ft/min. A mask is placed over the laminate prior to the trailing edge offluid in order to prevent curing outside of the patterned area. Placethe substrate-mold into the UV flood chamber and cured for 1 minute.Peel the Fluorocur mold from the PET substrate. The mold is thenrepositioned and nipped such that the nip point is on the patternedarea, and a bead of the aforementioned UV-curable liquid is applied atthe nip point. Similar to above, the mold is uniformly rolled out incontact with the substrate, and masked at the trailing end prior to theend of the patterned area. The substrate is placed into the UV chamberand cured for 1 minute. The second mold is then removed to reveal asecond cured, patterned area adjoining the first by a seam. Uncuredliquid residue is then washed from the patterned area, including theseam, with 2-isopropanol and dried. The dimensions of this seam areapproximately 2 micrometers in width and 250 nm in height. An AFM imageof this seam is given in FIG. 6.

Example 4

Thin FLUOROCUR® molds were produced by laminating a thin film ofFLUOROCUR® resin between a master template having a patterned array of200×200 nm cylindrical posts and a 6″ wide sheet of PET (MELINEX® D316,DuPont Teijin Films). The mold was placed in a UV flood curing chamberand exposed to UV (approximate output of 125 mW/cm²) for 4 minutes. ThePET-Fluorocur laminate was then peeled from the master and trimmed. Theapproximate patterned area of the mold is 5″×5″ square. The Fluorocurthin molds are then used to tile a larger area pattern on acrylic usingthe following steps.

The acrylic is coated with a tie layer by depositing a film of thetie-layer polymer (from example 1) in a chloroform solution at 15 w/w %via lamination between the acrylic and a PET film, allowing the laminateto sit for approximately 15 h, then removing the film to expose atie-layer coating. Place the acrylic on a steel plate laminator, and nipthe edge of the mold on the acrylic substrate using a rubber roll(durometer ˜50) at a nip pressure of ˜15 psi. Apply a bead of uv curableliquid (Trimethylolpropane ethoxylate (14/3 EO/OH triacrylate, averageMn 428, Sigma-Aldrich, 1 w/w % diphenyl(2,4,6-trimethylbenzoyl)phosphineoxide/2-hydroxy-2-methylpropiophenone 50:50 blend) at the nip point withan approximate volume of 50 μL at the nip point. Uniformly roll the moldin contact with the substrate at a rate of 0.5-1 ft/min. The bead ofliquid should be exhausted before the end of the mold (starve point),such that the mold is in contact with the acrylic substrate at the end.Place the substrate-mold into the UV flood chamber and cure for 1minute. Peel the Fluorocur mold from the PET substrate. The mold is thenrepositioned and nipped such that the nip point is on the patternedarea, before the starve point, and a bead of liquid of defined volume isapplied at the nip point. Similar to above, the mold is uniformly rolledout in contact with the substrate, again exhausting the bead before theend. The substrate is placed into the UV chamber and cured for 1 minute.The second mold is then removed to reveal a second cured, patterned areaadjoining the first by a seam. The dimensions of this seam areapproximately 3 micrometers width and 500 nm height.

Example 5

Thin FLUOROCUR® molds were produced by laminating a thin film ofFluorocur® OAE-01 resin between a master template having a patternedarray of 200×200 nm cylindrical posts and a 6″ wide sheet of PET(MELINEX® D316, DuPont Teijin Films). The mold was placed in a UV floodcuring chamber and exposed to UV (approximate output of 125 mW/cm²) for4 minutes. The PET-Fluorocur laminate was then peeled from the masterand trimmed. The approximate patterned area of the mold is 5″×5″ square.The Fluorocur thin molds can then be used to tile a larger area patternon PET using the following steps.

First, a piece of PET substrate can be cut in a dimension slightlylarger than the desired tiled size. A UV mask can be applied to theunpatterned side of the mold, either directly on the mold or as a secondlayer. The patterned side of the mold can be coated with a uniform thinlayer of TEGO RC 711, a UV curable resin, formulated with 1%diphenyl(2,4,6-trimethylbenzoyl)phosphineoxide/2-hydroxy-2-methylpropiophenone blend as a photoinititiator usinga slot or bar (mayer rod) coater. The edge of the mold would be placedon the PET substrate, and nipped in place using pressure of ˜15 psibetween a steel roller and a rubber roller of durometer 50-65. The moldcan be rolled out in contact with the substrate at a rate of 0.5-1ft/min, rolling in a direction away from the seam as shown, for example,in the embodiment depicted in FIG. 4C. Additional masking material canbe added if desired. The substrate-mold would be placed into the UVflood chamber (collimated UV) and cured for approximately 20 seconds.The Fluorocur mold can then be peeled from the PET substrate. The areaunderneath the mold exposed to the UV would be cured into a pattern thatreflects the pattern of the mold, while the masked area around the moldwould not cure. The entire mold would then be recoated with uv curableresin. One edge can be laid over the patterned area and nipped in place.The mold can then be rolled out in a similar manner away from the seampoint. Additional masking material can be added if desired. Thesubstrate would be placed into the UV chamber and cured for 20 seconds.The second mold would then removed to reveal a second cured, patternedarea adjoining the first by a seam, as shown, for example, in theembodiment depicted in FIG. 4F. The remaining uncured areas can bewashed away with IPA. The dimensions of this seam would be approximately3 micrometers in width and 1 micrometer in height.

While the invention has been described above with respect to particularembodiments, modifications and substitutions within the spirit and scopeof the invention will be apparent to those of skill in the art. Itshould also be apparent that individual elements identified herein asbelonging to a particular embodiment may be included in otherembodiments of the invention. The present invention may be embodied inother specific forms without departing from the central attributesthereof. Therefore, the illustrated and described embodiments andexamples should be considered in all respects as illustrative and notrestrictive, reference being made to the appended claims to indicate thescope of the invention.

1.-3. (canceled)
 4. A method for tiling patterned areas, comprising: a. depositing a predetermined thickness of a curable material; b. contacting a first portion of the curable material with a mold; c. curing the first portion of the curable material; d. removing the mold from the cured first portion of the curable material; e. contacting a second portion of the curable material with the mold, such that the mold also contacts a portion of the cured first portion of the curable material; f. curing the second portion of the curable material; and g. removing the mold to yield a seam between the cured first portion of the curable material and the cured second portion of the curable material, wherein the seam has a dimension less than about 20 micrometers.
 5. The method of claim 4, further comprising, prior to step b., curing the curable material to a thickness less than the predetermined thickness such that a surface of the curable material remains substantially uncured.
 6. The method of claim 5, further comprising controlling a thickness of the substantially uncured surface by controlling an oxygen concentration to which the curable material is exposed.
 7. The method of claim 4, wherein the dimension of the seam is less than about 5 micrometers.
 8. The method of claim 4, wherein the dimension of the seam is less than about 500 nanometers.
 9. The method of claim 4, wherein curing the first portion of the curable material comprises treating substantially all of the curable material with radiation while the first portion of the curable material is substantially protected from exposure to oxygen.
 10. The method of claim 4, wherein curing the first portion of the curable material causes the first portion of the curable material to retain a pattern of the mold when the mold is removed from the first portion of the material.
 11. The method of claim 4, wherein curing the first portion of the curable material forms a first patterned region in the curable material and curing the second portion of the curable material forms a second patterned region in the curable material, and wherein the seam between the first patterned region and the second patterned region has a height less than about 1 micrometer.
 12. A method for fabricating a substantially seamless pattern, comprising; a. providing a first portion of curable material between a mold and a substrate proximate a nip point; b. passing the first portion of curable material, the mold, and the substrate through the nip point; c. curing the first portion of curable material to form a first cured portion; d. removing the mold from the first cured portion; e. providing a second portion of curable material over at least a portion of the first cured portion between the mold and the substrate; f. passing the second portion of curable material, the mold, and the substrate through the nip point; g. curing the second portion of curable material to form a second cured portion; and h. removing the mold such that a seam between the first cured portion and the second cured portion has a dimension less than about 5 micrometers.
 13. The method of claim 12, wherein step b. results in depletion of the first portion of curable material prior to the mold and substrate exiting the nip point such that the curable material tapers to depletion between the mold and substrate.
 14. The method of claim 13, wherein providing a second portion of curable material in step e. results in adding the second portion of curable material to at least a portion of the depleted portion of the first cured portion such that the second portion substantially fills the tapered depletion to a pre-depletion thickness of curable material.
 15. The method of claim 12, wherein the mold comprises a fluoropolymer.
 16. The method of claim 12, wherein the dimension of the seam is less than about 1 micrometer.
 17. The method of claim 12, wherein the dimension of the seam is less than about 500 nanometers.
 18. The method of claim 12, wherein curing the first portion of curable material forms a first patterned region in the first cured portion and curing the second portion of curable material forms a second patterned region in the second cured portion, and wherein a seam between the first patterned region and the second patterned region has a dimension less than about 250 nanometers.
 19. A method for tiling patterned areas, comprising: distributing a first volume of curable material between a mold and a substrate, wherein when distributed the first volume undercoats the mold; curing the first volume to form a first cured area; separating the mold from the substrate, wherein the first cured area remains coupled with the substrate; distributing a second volume of curable material adjacent the first cured area between the mold and the substrate, wherein when distributed the second volume undercoats the mold and overlaps the first cured area; curing the second volume to form a second cured area; and separating the mold from the substrate, wherein the first and second cured areas remain coupled with the substrate.
 20. The method of claim 19, wherein the overlapped first and second cured areas result in a seam having a dimension of less than about 20 micrometers.
 21. The method of claim 20, wherein the dimension of the seam is a width of the seam or a height of the seam.
 22. The method of claim 20, wherein the dimension is less than 1 micrometer and is a height dimension or a width dimension. 